There's a common 'backyard weed' (known to be edible) known as (sp?) Sorrel. Should be familiar to most, it sprouts as a tricot of heart shaped leaves, and has a quite unique refreshingly sour taste. I have some soaking in PG. If you never hear from me again, it was a terrible idea. Wish me luck.. seriously, grab a sprig and have a munch, it's interestingly sour.
Sorrel is a tender perennial with large leaves, resembling spinach that you would not normally find wild. Sorrel is very tasty and I keep it in my garden, great for soups, sandwiches and herb mixes, and lightly in salads, tasting a bit like unripe wild strawberries.
Wood sorrel (also known as oxalis) is a wild herb with small heart-shaped leaves and small yellow flowers high in oxalic acid. I'm a big proponent of people harvesting oxalis, and I feel like your 17 lbs of rhubarb below might be a reference to one of my posts suggesting it's consumption on a permaculture, homebrewing or wildcrafting board. Oxalic acid is prevalent in many green leafy foods, and for some reason, rhubarb and oxalis wound up with a bad rap for it.
You are talking about wood sorrel.
While I am a fan of oxalis, and I think oxalic acid toxicity is very overblown, inhaling it is known to produce effects, such as irritation of the respiratory tract, ulceration of the mucous membranes, headaches, nervousness, cough, vomiting, emaciation, back pain (due to kidney injury), and weakness.
Try what you want, but please leave a note explaining what you're attempting, and don't send them here - it's not our fault! :)
>The plant's sharp taste is due to oxalic acid, which is mildly toxic.
Don't do it.
You'll have to eat approximately 17 whole rhubarbs to get a deadly dose of oxalic acid so he should be fine. :)
UPDATE: Tried a tiny bit. Used the white part of the root (from young sprouts) as the leaves released chlorophyll.
Notes: No sour bite, in fact devoid of any flavour. On a positive note, no lung irritation.
Conclusion: No such thing as a failed experiment, but this came close.